Background: Although there are growing evidences linking Chlamydophila pneumoniae infection to myocardial infarction, it remains controversial. The authors intended to assess whether C. pneumoniae infection is associated with myocardial infarction.

Methods: Sera and peripheral mononuclear cells (PMNCs) were collected from 54 cases of acute myocardial infarction (MI), 33 cases of old MI, and 60 normal controls. Anti-C. pneumoniae IgG and IgM antibodies were measured using a microimmunofluorescence (mIF) method, and C. pneumoniae DNA was detected using polymerase chain reaction (PCR).

Results: Seropositivity of anti-C. pneumoniae IgM antibody by mIF was shown 5.0% in control group, 29.6% (OR=8.00) in the acute MI and 6.1% (OR=1.23) in old MI group. Seropositivity of antiC. pneumoniae IgG antibody were 60.0 % in control group, 92.6% (OR=8.33) in the acute MI and 87.9% (OR= 4.83) in old MI group. The antibody titers in the acute MI and old MI group tended to be higher compared to those in control group. No C. pneumoniae DNA was detected in any case by PCR.

Conclusion: The seropositivity and antibody titers were significantly higher in the acute MI and old MI group than in control group, suggesting that C. pneumoniae infection may be a risk factor for myocardial infarction. (Korean J Clin Microbiol 2005;8(1):10-16)